Hi.

I've noticed that the "s" at the end of "les" and "des" is pronounced sometimes, but sometimes isn't. For example: it is pronounced in "les hommes" but isn't in "les femmes"; it is pronounced in "des hommes", but isn't in "des femmes".

I inferred that it's pronounced when the next word starts with a vowel sound, and isn't when it starts with a consonant sound. Am I correct?