Lorelei is fighting Team Rocket inside the Ice Cave, once you get HM:07 - Waterfall. Navigate through the cave to get the HM, then use it to go up the waterfall in the beginning of the cave. Take the ladder, and you'll find her.
(Also, it's nice to know that you can find additional wild Lapras in the room where Lorelei is. However, they only have an encounter rate of about 1%, roughly.)
After arriving at Four Island, you must work your way to the Ice Cave, there will be maze like obstacles to pass, you will find Lorelei in a room of mostly water.
4 island in icefall cave to reach lorelei you need to find HM7 inside icefall cave.
she's on 4 island in the cave to your right when you enter 4 island.
She is in the cave on 4 island. When you meet here there she returns to the elite4.
To face the Elite 4 a second time, you need to have: Met with Lorelei on Island 4. Completed the Ruby/Sapphire plot (involving Rockets.) Lorelei will return to the Elite 4 and you can then face them again.
Lorelei of the Elite Four is in 4 island of the rainbow islands. You need to go there to IceFall cave and help Lorelei beat Team Rocket. Then you need to get 2 passwords for the Rocket Warehouse on 5 island. After you beat Team Rocket in the Warehouse, Lorelei will come back to the Elite Four and you can fight them.
4 island in icefall cave.
4 island in icefall cave to reach lorelei you need to find HM7 inside icefall cave.
she's on 4 island in the cave to your right when you enter 4 island.
her house is on four island.
To help Lorelei in Pokemon Firered, you must travel to Four island (Floe island) and enter the Ice Cave. Work your way through the maze-like obsticles and you should find Lorelei in a room with mostly water. She will tell you what to do from there.
First, go to four island and go to the ice cave and complete the task. Once you get waterfall and defeat team rocket with Lorelei. Lorelei is back to the Kanto Elite 4.
Lorelei returns to the Elite 4 after you encounter her on Island 4.
She is in the cave on 4 island. When you meet here there she returns to the elite4.
If lorelei is not in her home on Four Island. Go to the Ice cave on the right. She is in there, fighting some rockets.
She goes to her home on 4 island and then to the Ice Cave , then she Goes back to the Elite 4 In other words, Lorelei goes back to her home town - which is Four Island. However, she is not in her house; Lorelei is found in the depths of Ice Cave where she is fighting Team Rocket. If you help her defeat them, she will return home and later, back to the Pokemon League to rejoin the Elite Four.
To face the Elite 4 a second time, you need to have: Met with Lorelei on Island 4. Completed the Ruby/Sapphire plot (involving Rockets.) Lorelei will return to the Elite 4 and you can then face them again.
You have to 'rescue' Lorelei in the icecavern at 4 island. To get there, you must have given the ruby to Celio. You find the ruby at ONE ISLAND, at Mt Ember. When you've completed the tasks above, you should have the rainbowpass aswell as the sevii islands pass. This allows you to get to the fourth island and help lorelei fend off the bad rocket guys. Then she should return to the elite four, and you'll be able to battle her.