I came up with a couple of interesting reads in defense of starting sentences with "but", "and", and "or":
* http://www.michbar.org/journal/article. ... olumeID=48
* http://michelle-strozykowski.suite101.c ... but-a74404
From William Zinsser (author of On Writing Well): "Many of us were taught that no sentence should begin with "but." If that's what you learned, unlearn it--here is no stronger word at the start. It announces total contrast with what has gone before, and the reader is primed for the change."
~S
Edited to add the following comments from my instructor:
Yes, you can start a sentence with the coordinating conjunctions "and" and "but" for a rhetorical effect. The following is from the New York Times:
Here is another read on the issue:Beginning With “But” (or “And”)
Another pet peeve of some After Deadline commenters is the use of “but” or “and” to begin a sentence — as in the third sentence of the previous section. Obviously, I don’t share their aversion.
It shouldn’t be overdone, but using coordinating conjunctions this way can provide a handy and very efficient transition. “But” is certainly preferable in many cases to the stilted “however,” and “and” is simpler than “in addition” or similar phrases.
I’d put this objection in the category of “Miss Thistlebottom’s hobgoblins.” That’s how the former Times language guru Theodore M. Bernstein described overly fastidious rules and usage myths a grade-school English teacher might invoke to keep her pupils’ prose on a very narrow path. (Familiar examples include “Never split an infinitive” and “Never end a sentence with a preposition.”)
The same is true with the conjunction but. A sentence beginning with "and" or "but" will tend to draw attention to itself and its transitional function. Writers should examine such sentences with two questions in mind: (1) would the sentence and paragraph function just as well without the initial conjunction? (2) should the sentence in question be connected to the previous sentence? If the initial conjunction still seems appropriate, use it.This is what R.W. Burchfield has to say about this use of and:
There is a persistent belief that it is improper to begin a sentence with And, but this prohibition has been cheerfully ignored by standard authors from Anglo-Saxon times onwards. An initial And is a useful aid to writers as the narrative continues.
~ from The New Fowler's Modern English Usage edited by R.W. Burchfield. Clarendon Press: Oxford, England. 1996. Used with the permission of Oxford University Press.
Thus, it is perfectly acceptable to use and and but to begin a sentence.