Michael hello,

ELAL and DL do codeshare but AFAIK there are no upgrades on this route using DL miles or a DL ticket. All the flights are on ELAL. Other flights to TLV include CO, Air Canada, and AA direct and UA, NW/KLM through Europe.

I'm not sure you will be able to grab an upgrade for the summer given your mileage situation, and the fact that the TLV route is a heavily traveled one in the summer (although this summer may be light.....)

Good luck.