So on my upgrade from Wheezy to Jessie, I found myself (amongst other issues) looking at a graphical interface where the mouse worked fine, but no mouse pointer was visible. After trying a few other things, it turned out that :-
gsettings set org.gnome.settings-daemon.plugins.cursor active false
Did the trick.
Of course that tip came from somewhere else, but as it worked for me, it’s worth making a note of.