Rename files using a list

I have several hundred scanned files that have numerical names like 123456.pdf. I have a spreadsheet containing the filenames in one column and a more descriptive name in the next column. I'd like to have hazel rename all the files in a folder with the more descriptive names by matching the filename in column A of the spreadsheet and renaming the file with the new filename in column B. Any suggestions on how I can accomplish this?

You'd have to use a script at the moment. I'm considering some sort of way of including lists/tables in a future release but still trying to work out the details. If you could provide some examples of the renamings you need to do, that will help inform any design decisions I make on this.