I'm writing about a web framework. Integral part of it is its lifecycle. Apparently (as for example my browser tells me), this is not the correct spelling. I should either use life cycle or life-cycle. Google Ngram confirms this. And I also had a look at Life cycle, life-cycle or lifecycle? and When should compound words be written as one word, with hyphens, or with spaces?.
However the specification uses exclusively lifecycle. It may be the short form of some kind of proper name Request Processing Lifecycle. But then again it uses the spelling lifecycle in a different context, like this: "A human readable string describing where this particular JSF application is in the software development lifecycle.". So I'm not sure about the "proper name".
But since the specification uses the spelling lifecycle, and I'm writing partly about the lifecycle defined by this specification, should I also use this spelling? Should I only using this spelling when I'm writing about this specific lifecycle and use life cycle when writing in a different context? Or should I always use life cycle?