All enemies in the game are permanently cloaked.
Immediately after the gondola ride following the battle with the Hunters, there will be a building with two turrets on it. Enter the building and turn to your right. There will be a box, jump on it. From there jump to the adjacent light fixture, then to the ledge. The ledge leads to the area with the two turrets.
Once there, Grenade Jump to get onto the roof area. Then, using Crouch jumping and/or Grenade Jumps, follow the right side perimeter of the building. Once you have gone as far as you can go you will find a small grassy area with two Stealth Elites holding Energy Swords (one can be assassinated the other cannot) in their "angry stance" and the Assassins Skull between them.
All enemies have permanent active camouflage.