I don't really understand your dependent clause. Ironically, your "Depending on..." sentence is just fine. The picnic was called off because of the weather forecast. Because of the weather forecast, the picnic was called of. I'll go if you ask me. If you ask me, I will go.
Those are examples of using the comma as you describe.
What is the word 'which' supposed to refer to in your sentence, wholegrain? And could you explain the intended meaning of your sentence (i.e. reword it)?
Are you Neil Armstrong? No, that doesn't work. "on which I walked that fateful day" says which moon. Use that dependent, independent structure for clauses that start with if, because, although, etc.