It does seem strange to loan out Lokonga in our position when we could keep him for insurance, but I would guess he's low on confidence and/or his attitude is off right now, to the extent that he's just not going to be much use at all. As I think we saw last Friday against City.
We have Partey/Jorginho, Xhaka/ESR, and Ødegaard/Vieira. That's pretty damn strong, and a much better set of options than we had for the first half of the season given Elneny isn't half the player Jorginho is, ESR was out injured, and Vieira now has more minutes and (a bit) more muscle.