Grammaire – Les Liaisons
Liaison occurs between two words when the second word begins with a vowel sound, that is, with a, e, i, o, u, and sometimes h & y.
In addition, consonants in liaisons sometimes change pronunciation. For example, an S is pronounced like a Z when it is in a liaison. Review the list below.
Letter – Sound
Compare the sounds
Sound files courtesy of french.about.com!