Hello,
no, as far as I know there´s no way to determine if the attachment control is clicked. There are only a 'Validating' and a 'Changed' event bound to the attachment control. You can´t control the file attachment process before the appropriate file is attached.
If the requirement are that the user has to fill out something other before he can attach a file I can recommend that you bound a conditional format rule using a section where you put in the file attachment control.
Regards,