Comma After an Objective Case Noun Clause Pulled to the Beginning of a Sentence
The Comma
Rulebase Summary
Use a comma after an objective case noun clause that has been pulled out of its natural word order to the beginning of the sentence. A noun clause that is the subject of the sentence is NOT out of order and does not take punctuation — it is in its natural position.
Examples
A. Where it was located I don't know.
A. Where it was located, I don't know.
Objective noun clause pulled to the front — comma needed.
Q. How long she waited, is the crucial question.
Q. How long she waited is the crucial question.
Noun clause is the subject — no comma. It is in its natural position.
Transcript Notes
Distinguish between a noun clause as the subject (no comma — it is in its natural place) and a noun clause as an object that has been moved to the front (comma — it is out of natural order and interrupts the flow).
Style Guide References (1)
BGGP