Follow Steps 1 to 3 above as for boiling artichokes.
Place a trivet at the bottom of the pressure cooker.
Add just enough water to reach the base of the trivet (about 1/2 to 1 cup of water).
Bring the water to the boil.
Squeeze the lemon juice over the cut side of the artichokes.
Place the artichokes on the trivet with the stems on top (and the cut side facing down).
Place the lid on the pressure cooker and cook on high pressure for about 15 minutes if you are using large globe artichokes. Otherwise, you may have to adjust the time if your artichokes are smaller.
At the end of the cooking time, release the pressure quickly.
Remove the lid of the pressure cooker carefully.
Test the artichokes for doneness. The outer leaves should come away from the stem easily.
If the artichokes need more cooking, replace the lid, bring the pressure cooker back to high pressure and cook for a few more minutes.
Follow Steps 8 to 10 above as for boiling artichokes.