Wikipedia article here
Never thought about this before, but after reading the wiki this issue so confusing and wide ranging that I think its difficult to have a “correct” form. Obviously what is “correct” is subjective to a large degree, but almost all “English” speakers would say the “Red Apple” but not the “Apple Red”, so I would suggest the “Red Apple” is correct. But this issue seems too complex.
For instance the wikipedia article even mentions this
Some British dialects (for example, Cockney) silence all initial h’s (h-dropping) and so employ “an” all the time: e.g., “an ‘elmet”. The article “an” is sometimes seen in such phrases as “an historic”, “an heroic” and “an hotel of excellence”
Which suggests an hotel may be correct depending on where you on from.
Apparently An is related to Ein in german and we have gradualy dropped the n. But apparently the process can work in reverse. ->
Supposedly the word apron should be napron. Napron” itself meant “little tablecloth” and is related to the word “napkin”. But it has ended up going from a napron to an apron.
Also the process can add an n to a word ie it should be an ewt but the n shifted to give a newt.
Which may mean if the cockey form kept developing we may end up with
An hotel -> a notel.