Pokemon Fire Red Lorelei is Missing?

You can never have a rematch with the Elite Four until you completely disband Team Rocket. As you already know, they're still poaching Pokemon. As you try to help Celio with his Ruby and Sapphire dilemna, you come across Team Rocket for the last time, at Five Island. In case you have no idea what to do, you go to Six Island, and go through the Dotted Hole, where you find a Sapphire at the bottom. Some moron steals it and says he'll sell it to Team Rocket. At that point, you go to Five Island, enter the hideout and shred them. They disband as soon as you beat the Admin, and you get the Sapphire back from that moron. You hand that Sapphire over to Celio, like you did with the Ruby, and he says you can trade to Ruby Sapphire and Emerald Version. After that's all done, you can go back to the Indigo Plateau, where Lorelei will be back. She has level 60 and higher Pokemon, so be ready.