Do you set off "and when" with commas?

For example,

Sim allowed his feet to be placed on the floor*, and when his daughter held out her arms, he leaned his weight into them.

Or would the sentence read as

Sim allowed his feet to be placed on the floor *and when his daughter held out her arms, he leaned his weight into them.

I think "Sim allowed his feet to be placed on the floor" and "he leaned his weight into them" are both independent clauses, but I don’t know if "and when his daughter held out her arms" is independent or dependent. I think it’s dependent but I want to be certain.