when i was a child, if we went away for a few days, or a week (to camp) when i came home, everything looked new to me

Reminds me of T.S. Eliot's famous words, of Troy:

"We shall not cease from exploration and the end of all our exploring will be to arrive where we started and see the place for the first time."

BTW I am certainly not fluent in French, but it looks to me like the phrase "avant verrais" translates into "before the truth", at least roughly. So it suggests to me that "avant verrais" is a glimpse of something before it happens, or precognition, or "premonition" as wseisber has already mentioned.

"deja vu", on the other hand, is the sense that you 'have already been there', as tho in another dimension, or a parallel dimension, of time and space, or in a past life. One does not have to believe in such things to experience the sensation, altho it might give one reason to be curious about the possibility.

Now that I think of it, Esmond's sense of "home" was clearly avant verrais. At least, it was clear for him.