Honestly never done this myself, but pretty sure all you need to do is include the proper hyperlink to Lync in the Website list in the user properties.
Check out S-061060.
For user details to display in a pop up window (while hovering over user name in explorer),
a) Microsoft® Communicator should be installed on the client and
b) Email information should be entered in user details – refer to “User Details.jpg” for details.
If the above two conditions are met, the option to chat and call through Communicator should be visible starting with Enterprise PDM 2013.
I haven't tried this out yet but will be testing soon.