Father Edward McNamara, professor of liturgy at the Regina Apostolorum Pontifical Athenaeum, answers this too in similar fashion. He points out that prior to the Vatican II reforms the "rule" was that one had to be there at least by the Offertory - however post conciliar theologians (not expressing a "rule" - answer more vaguely. Fr. McNamara uses a baseball analogy and says:
To say that there is a particular moment before or after which we are either "out" or "safe," so to speak, is to give the wrong message and hint that, in the long run, some parts of the Mass are really not all that important. It may also give some less fervent souls a yardstick for arriving in a tardy manner.So, while he hasn't stated a rule, he has given his opinion that if one is not there by the time of Consecration, then they have "not attended Mass, should not receive Communion, and if it is a Sunday, go to another Mass."
Although I prefer not to hazard giving a precise cutoff moment, certainly someone who arrives after the consecration has not attended Mass, should not receive Communion, and if it is a Sunday, go to another Mass.
Arriving on time is not just a question of obligation but of love and respect for Our Lord who has gathered us together to share his gifts, and who has some grace to communicate to us in each part of the Mass.
From my perspective, which I grant you is from the more traditional (Pre-Vatican II) view is in line with what Fr. McNamara refers to - you need to be there pre-Offertory. I am also of the mindset that the focal point of the Mass is the Consecration, and to miss that means you have not fulfilled your Sunday obligation.
How late is "too late" to receive Holy Communion? While one might fulfill their Sunday obligation if they arrive prior to the Consecration - should they receive Holy Communion? Now, keep in mind, one does not have to receive Holy Communion to fulfill the Sunday obligation; even the excommunicated, who may not receive Communion, are still obliged to attend Mass every Sunday and holy day of obligation. With that in mind, while it may be "lawful" for one to receive the Eucharist after arriving late - should they? Things to consider may include causing another to sin because they may see this as scandalous (whether it is or not) and by your action be distracted and drift into gossip. While it's not your sin, did you cause it?
Another factor though, and perhaps more important, is do you NEED to go to Holy Communion? I know there are times when I truly feel I NEED to receive the Eucharist, and to miss it hurts my soul so much it's almost a physical pain. In such circumstances, I would still approach Communion - but if I arrived "late" - I would sit in the rear and do my best to cause as little disturbance and distraction as possible.
The "Catholicism.About" page offers that there is no real "time limit" on how late one can receive Holy Communion, if they are still distributing it - you may receive it - HOWEVER - just receiving the Eucharist does not constitute fulfilling the Sunday Duty (obligation).
If you come into Mass on Sunday or a Holy Day of Obligation at the time that Communion is being distributed, you may receive Communion, but you have not fulfilled your Sunday Duty. To fulfill your Sunday Duty, you need to attend the entire Mass. If, through no fault of your own, you arrive late, or important circumstances require you to leave early, you've still fulfilled your Sunday Duty. But if you leave early to get a better seat at the buffet, or you arrive late because you decided to sleep in, then you haven't fulfilled your Sunday Duty.The opinion expressed by this "expert" seems a bit contradictory though. He says that one may arrive late and still receive Communion, but may not have fulfilled their Sunday Duty, and goes on to explain that on days which are not obliged (daily Mass) sometimes Eucharist is distributed before, during and even after Mass. I would add, to those who are bedbound and Eucharist is distributed to them after Mass, they have not attended Mass - and yet are licitly receiving Holy Communion. The part I would like to see him clarify is the point about it not being a mortal sin to receive (I agree) but one would need to go to another Mass that day (if it is a Sunday or holy day of obligation). If that Mass is the last Mass of the day and/or the person has no intention of trying to get to another Mass - then if they have not fulfilled their Sunday obligation (or duty) and since there is no further remedy or intent to remedy, then they are already in mortal sin and should not receive the Body and/or Blood of our Lord - for they would be doing so unworthily (1 Corinthians 11:27-29).
The bottom line is, if you have missed ANY PART of the Mass for an unworthy reason, then you do not fulfill your Sunday obligation and if there is no opportunity to attend another Mass, then you are in mortal sin and should not receive the Eucharist. As for being late for a "worthy" reason - one would have to HONESTLY self-examine and ask their self if they should receive Communion. Whether one draws the line at the Offertory or the Consecration (and definitely not past the Consecration) the question should be SHOULD they receive the Eucharist, and that is a question only THEY can answer after a careful self-examination.
And, if I may poke a little jab at those who leave Mass right after receiving... Mass is NOT OVER YET! If you leave early, especially for an unworthy reason, then you have not fulfilled your Sunday obligation - and mere receiving of the Eucharist does not fulfill your duty. So, to leave early can be a mortal sin. The real "rule of thumb" here should be: "The priest is the last person to enter Mass and the first to leave." If you arrive after the priest has entered or leave before he has processed out - you have some serious self-examination to do. Remember who the first one to leave Mass early was? Judas Iscariot.