This is on my workstation, and I'm the only one logging into it.
And the only possible way for me to run lsclient.exe, is by manually running it. It's not configured on any of my login scripts / group policy or anything. In fact, during the last test, I set a software restriction policy in group policy on my workstation to disallow the execution of lsclient.exe.
I can delete my workstation from the GUI console, periodically check the lansweeper web interface, and boom, it shows up again, even though execution of lsclient.exe is denied.
EDIT: Just watched it happen again, and was monitoring processes with Process Explorer, and lsclient.exe was never executed.