When an Excel file is locked on a network share, how does it know who locked the file?

We are using Excel 2010 and sometimes users are working from a network share. When a user on the network opens the file in Excel, the file is locked for editing - this is the expected behavior. When another user tries to open the file, Excel gives the message

[filename] is locked for editing by 'John Doe'

The problem is, the user is always this one particular user's name, no matter who actually has the file open. Where does Excel get this info, and how do I fix it?

Update: I should have mentioned that in Excel, under Options (General), the correct user names have been set up. That is not where this user name is coming from.

Excel creates a hidden file on the share called ~$filename where filename is the original file. That hidden file contains the name of the user who has the file locked. The name comes from the Office options, as others have stated.

For some reason that file was not deleted properly when the file was closed. Oddly, everything still works - the next user to open the file can still edit and save, but it looks like it's checked out to someone else. And even after editing, saving and closing Excel, that hidden file is still not deleted.

After manually deleting the file, everything works properly again.

Change the name in Excel for the users to be the actual users name under file>options>general