Two handy grammar articles on conjunctions

Yes, you CAN begin a sentence with "and" or "but"!  Differences discussed between coordinating and subordinating conjunctions.

http://www.dailywritingtips.com/can-and-or-but-begin-a-sentence/
http://blog.oxforddictionaries.com/2012/01/can-i-start-a-sentence-with-a-conjunction/

 Article 1: "When most of us were in school, our English teachers made a point of forbidding us to begin a sentence with “and” or “but.” It’s one of those lessons that stuck, and writers today go to extreme lengths to avoid it. Is it really forbidden, though? Or is it just a myth?"

Article 2: "No, young lady, it is an unspeakable offence against the English language, and I will mark any such errors with a large red circle and make a public example of you by reading out your ungrammatical prose to the whole class.’"

: )