Sitstart completely right, traverse to the left as for Le Toit Cornélien (rallongé) (or with the lowest ledge of Le Sous-Sol if that one is dry), continue with low holds up to the start of Retour d'Ascenseur, climb the roof, come back in Panne d'Ascenseur and finish above the starting point.
NB: the loop can also be done in the other way around (same grade).