Tips on capitalisation: job titles, academic degrees, government units
The general tendency is towards lowercase rather than initial capitals, which is in part a reflection of today’s less-formal, less-deferential society. As with any aspect of style, though, it is impossible to be wholly consistent; aim for coherence and consistency, but not at the expense of clarity.
Use the capitalised form when naming a specific person holding a specific position. But, write a job title in all lowercase when referring to the position (rather than the person) or when it is descriptive.
Use initial capitals for the official name of a degree. But, use lowercase if the designation of the degree is general or descriptive.
Use initial capitals when the full name is used (1); use all lowercase when the name is abbreviated or paraphrased (2), or when it is the unofficial translation of a non-English name (3).