Lower casing especific words

I'm not familiar with reg ex operators, so I need help.

I want to lower case all the articles (a, an, the), conjunctions (and, or, but) and small prepositions (in, out, on, of, to, at) of tags and file names, but not if they're the first word. Explaining:

My files are like this:
The Name Of The Track

I want them like this:
The Name of the Track

But not like this:
the Name of the Track

What should I do? Currently using version 2.48

you should probably check out /t/11684/1 for the awesome script(s) that were created

It seems to have exactly what I wanted. Thanks!