And yes, I am aware that a paragraph is not defined by the number of sentences it contains. However, I am also aware that a paragraph's purpose is to group a number of sentences along a particular theme. Sure, one can write a single sentence paragraph, but it is considered bad practise within the realm of factual writing. But just as starting a sentence with 'but' or 'and' is theoretically 'against the rules', there are occasions where a creative writer would feel compelled to rebel and write a single sentence paragraph. The effect is to give that sentence undue emphasis, which IMO, is rarely appropriate in journalism: which necessarily requires balance.
Here endeth the lesson : p