Paul Allardyce, "Stops", Or How to Punctuate
“ XVI. A conjunction marks a transition to something new—enforcing, qualifying, or explaining, what has gone before, and is therefore generally preceded by some point. The proper point before a conjunction is determined by many circumstances: among others, by the more or less close connexion of the things joined, by the number of words, and by the use of points for other purposes in the same sentence. ”
