A site I often return to for such punctuation advice states:
Originally Posted by david.kosson
However, don't put a comma after the main clause when a dependent (subordinate) clause follows it (except for cases of extreme contrast).
1. She was late for class, because her alarm clock was broken.
2. The cat scratched at the door, while I was eating.
3. She was still quite upset, although she had won the Oscar.
(correct: extreme contrast)