Was the black permananent or fade out? If permanent no chance, if fade out wait for it to go as close back to your natural colour then see the hairdresser. Depending on what your hair condition is like then they may bleach it, but it will not go a platinum colour first time round. If you colour your hair a lot or use straighteners and your hair isn;t in great condition they may avoid using bleach and just use a magi-lite colour which just lifts the colour - although you run the risk of it going orangey. You may be better off with highlights rather than a block colour, but to be honest i would doubt that any hairdresser would put enough bleach on dyed black hair to get it blonde. Take your time with it, i know it's boring and frustrating but if you go ahead and bleach it anyway, chances are your hair will snap off - literally the whole highlight an inch from your end, not just the ends. So the short answer really is no i'm afriad, but get a consultation at a decent salon and they'll advise you properly.