Can Sentences Start with "Which"?

At the high levels of writing, (upper-class English majors and graduate-level) students do not think about a lot of the problems/mistakes seen at the lower levels. We do things correctly automatically and our focus lies more in the essay ideas.

Once I read the essay, I understand what went wrong with the grammar/punctuation mistakes a lot better.

Here is something I notice though.

Students like to start sentences with "which" a lot.

The man saw the double rainbow. Which caused him to lose his mind.


Combine them.

The man saw the double rainbow, which caused him to lose his mind.


In some instances, starting the sentence with "which" is okay, especially when the writer is trying to make a point. It is supposed to be used that way sparingly though and I do not believe students are doing it sparingly on purpose in my classes.

Read this Grammar Girl article for further explanation.

http://www.quickanddirtytips.com/education/grammar/can-you-start-a-sentence-with-%E2%80%9Cwhich%E2%80%9D

I actually played the Double Rainbow video for my MW 10:35 class. (As for why, I guess that is a bit questionable!)