How to rename to all lowercase

Is it possible to create a rename function that will make all value lowercase except any acronyms?

Before: Database Parameters for DB2.pdf
After: database parameters for DB2.pdf

I guess it would have to analyze that any string that is already all-uppercase, ignore it. But if the string begins with an uppercase character followed by a lowercase (or multiples), then make that string all lowercase.

I don't think you can do this at the moment, sorry.

Opus has some options for changing the case of filenames but this particular scheme isn't one of them. I don't think you can do it with regular expressions either.