Conventions of Composition Rule 11

Rules: An adverbial clause at the beginning of a sentence must be followed by a comma. An adverbial clause at the end of a sentence should be preceded by a comma only if the clause is inessential (presented merely as additional or incidental information).

Examples:

Wrong: When you start with an adverbial clause you need to follow it with a comma.

Better: When you start with an adverbial clause, you need to follow it with a comma.

Correct: Come to our house after you finish work today. (Don't leave work early.)

Correct: Make hay while the sun shines. (Don't make hay at night.)

Correct: I am sorry I cannot go with you now, although perhaps I could some other day.

Practice deciding if and where these sentences could take commas:

1. If he trains his dog to joggle (jog and juggle simultaneously) he could make a lot of money.
2. Craig would love to sing in the musical if he gets a starring role.
3. Buying a new car can cause stress when money becomes tight.
4. Because she understood fractals she aced the exam.

Resources for further explanation of how to punctuate sentences containing adverbial clauses:

Towson's Dependent Clauses

Your Dictionary's Adverb Clauses