Originally Posted by Kurald Galain
Yes, of course. The thing is that you're retroactively assuming
that it did, which is the joke. A bit meta, isn't it?
I can see what you mean, but I don't think that's right. In the first case, Elan specifically invokes the idea of retroactive assumption, whereas in the latter, he simply states that the training had taken place. There's a difference between a character explicitly trying to "game the system" versus just stating something to have happened off-panel.
Given the whole fight and reconciliation after the "Elanicalicus" incident, the best explanation is that Elan is simply telling the truth, and Vaarsuvius has been training him magically despite Elan not actually multiclassing to wizard. That's not really an assumption, that's just believing what a character says (and noting its consistency with other evidence).