A sentence beginning with a dependent clause usually requires a comma after the clause:
'If you wish to see a movie, let's leave now.'
When we begin with a dependent clause after a coordinating conjunction,
do we use a comma at the beginning and end of the dependent clause to
set it off as a dependent clause?
'I have finished lunch, and
, if you wish to see a movie
, let's leave now.'
Or do we just use one at the end of the dependent clause:
'I have finished lunch, and if you wish to see a movie
, let's leave now.'
There would, of course, be no problem if the sentence read:
'I have finished lunch, and let's leave now if you wish to see a movie.'