The modern thinking on split infinitives is that they are fine. As I've mentioned before on another question, in the same way Dr Johnson standardised and set many spellings upon publishing his dictionary, there was a Scottish school marm who wrote a grammar text which became ubiquitous. This text stated that splitting infinitives was a no no and so it was for many years. Since the purpose of grammar is the facilitation of understanding, modern thinking is tending towards the idea that split infinitives are a funtional and understandable way of writing. After all, anywhere else you might add a descrition to something, it goes between the article and the object: i.e. A blue pencil rather than the clumsy 'A pencil which was blue', so why not here? Hope this helps.