I don’t believe it’s changed in PsychoPy, but I think you might be able to make a code component that will do it. Try adding this javascript code to the beginning of the routine where you want to hide it, or if that doesn’t work, on each frame in that routine:
document.body.style.cursor='none';
You may need to add the following code in the next routine to un-hide it:
document.body.style.cursor='auto';