Go to the souvenier shop and he should be in there hope this helps. Oh and you might want to pack some potions and full restores because there is a whole Team Rocket sidequest.
lance goes to the souviner shop in mahogany
After you catch the Red Gyarados, Lance will be at the shoreline of The Lake of Rage.
He appears after you catch/kill the red gyarados
Meet Lance At the Wannabe Pokemart or Suspicious House
You first find lance after beating the Red Gyarados, then you meet him in the souvenir shop, and battle team rocket with him. You will also see him again as Pokemon League Champ.lance is the johto champion so you could find him after you beat the elite fourAt the lake of rage in mahoganyIf you have not met him yet, Lance is at the Lake of Rage. Once you defeat the Red Gyarados, he will be reading a sign. Go and talk to him to continue the game.
In the town under it, in the Gift shop with a radar next to it.
Team Rocket doesn't appear at the Lake of Rage, but there is a bunch of Gyrado's that were forced to evolve by Team Rocket, if that's what you're looking for. At the Lake of Rage, you have to battle or catch the Red Gyarados, and then meet Lance, the Champion of Johto.
To get past the "Lake of Rage Dilemma", you have to surf out to the Red Gyarados and either capture it or defeat it. Then surf back to shore and Lance, the champion, will tell you what to do from there.
you go to the lake of rage surf on the water catch or kill the red gyardos than lance will appear.
after you have defeated the team rocket go on to lake of rage.........near mahogany town where the hideout was if i think you were asking....
at the lake of rage
You find lance outside the lake of rage looking at a sign, inside Team Rocket HQ (aka gift shop in mahogohny town) and in the champions room were he is waiting to battle you. Also in the dragons den where you are in a double battle with the passer by boy against lance and the 8th gym leader.