I read in the forums that holding the middle mouse button should allow me to rotate the map. It doesn't.
I have a Logitech MX series mouse with a scroll wheel/middle button. The scrolling works fine for zoom in and zoom out even though rotate does not.
As a workaround, I went into Windows XP's Mouse Properties, Buttons Tab, and assigned a side button to 'Middle Button'. This breaks normal use of that button, but allows me to use it as a rotate button while playing Elemental. The default setting for what would normally be my middle button/scroll wheel is 'Universal Scroll' according to the properties panel.