Put the olive oil in a medium pot and set over medium-high heat. When hot, put in the onion, garlic, and ginger. Stir and saute 2-3 minutes, or until the onion softens and just starts to brown. Add the curry powder and stir for 10 seconds. Now put in the cloves, potato, and carrot. Stir for a few seconds, then add the lentils and stock. Stir and bring to a boil. Cover partially, leaving the lid slightly ajar, turn the heat down to low, and cook gently for 45 minutes, or until the lentils are completely soft. Add the salt and pepper to taste.