Well I won't replay the entire Lake route again just to remember where exactly the game says that he's taller. But it definitely happened.
Directly after the power comes back on after everyone has gone to there separate hovels to recover Arvo and Lake are talking. Arvo says something about not being able to carry lake back this time preferably and then thinks to himself, "could I, even? Likely not, my bet is that Lake weighs the same as me, being a tad taller, but also slimmer."
I have yet to encounter the line you were thinking of. The route was of course Lake's route.