electronic choke

Good question. Early electric chokes got power at switch on but if the engine wasn't running or even hard to start the choke would open early and drain battery too. Laterthose thinkers wired the choke through a oil presure sender or somewhere to apply current with engine running only.
For you I want to suggest a relay for choke power supply. To signal that relay with your oil pressure sender may not work since the sender only sees 5 to 6 volts. May work or may just screw with the gauge reading.
I should have a good answer for your good question but dont.