I tend to agree that the outcome of the Notre Dame game could have a significant influence on our selection potential.
Army is currently ranked 16th in the two national polls, and 18 teams are selected; so it would seem that they have a reasonable chance of making it if they go the the PL championship game and have a good game against Loyola. There are ten conferences in lacrosse, and the champion of each gets an AQ bid. That leaves 8 teams that will be selected at large from those 10 conferences (along with the one independent, Johns Hopkins which is almost certain to get a bid).
I haven't paid much attention to how teams get selected, but if the selection committee tends to spread out bids across conferences, I think our chances are reasonably good if we come in second in the PL. Of the top 18 ranked teams, 6 are from the ACC and 5 are from the Ivy League; so if there's some pressure to include more teams from other conferences, Army's chances improve. If we beat Notre Dame, it seems like it would be hard for the selection committee to pick them and not us.
And while we have a few bottom feeders in the PL conference, we also have four teams that have ranked in the top 20 at one time or another this season; so it's one of the more respectable conferences. At this point in time, I'd rate the PL as the third toughest conference. That will change next year when the Big Ten adds lacrosse as a conference sport with Md, Rutgers, Johns Hopkins, and Penn State in the mix. Ohio State and Michigan are still neophyte lacrosse programs, but that could change quickly.