Most contractions are just simple elisions in French (one or two
final letters are replaced by an apostrophe). Only four are non-
trivial, each of them involve one preposition and one article
(they don't apply when le or les are pronouns): - au = “à le” -
aux = “à les” - du = “de le” - des = “de les” Those contractions
are always performed, except when the article le, which is part
of these compounds, can be elided first (example: de l'abandon,
à l'abandon). This is actually the only point you should be
careful about. Now, because au, à or aux begin with a vowel, the
word that precedes might also require an elision (but this was
expected): Jusqu'aux premières lueurs du soleil. In very rare
situations, several elisions could be chained.