Starting a sentence with a conjunction
The Rule: There is widespread belief that it is incorrect to start a sentence with a co-ordinating conjunction such as and, but and or. However, this is not the case. In fact, a substantial percentage (often as many as 10 percent) of the sentences in first-rate writing begin with conjunctions.
‘And the idea that and must not begin a sentence, or even a paragraph, is an empty superstition. The same goes for but. Indeed either word can give unimprovably early warning of the sort of thing that is to follow.’
Kingsley Amis, The King’s English (1997)