The orchestra I play in is planning to commission a piece of music for our 50th anniversary concert in 2017. We've commissioned music in the past, and had music written for us, by amateur composers. These were great, and in a few cases the composers are also recorded by professional orchestras, but the composers had day jobs other than composing.

I don't know what term to use when referring to a composer who is not an amateur: one who makes their income from composing. The obvious antonym to "amateur" is "professional" but the term "professional composer" does not sound right. I cannot imagine anyone writing, for example, that Arvo Pärt is a professional composer.

What is a nuanced way to refer to a composer's professional standing?