Bring broth to simmer in saucepan. Remove from heat. Cover; keep warm.
Melt 1 T butter with oil in heavy pot over medium-high heat. Add onion, sauté until soft and golden, about 5 minutes.
Pat artichokes dry and add to pot. Sprinkle with salt and pepper. Cover and cook until artichokes begin to brown, stirring often, about 8 minutes.
Add Arborio rice, stir 2 minutes. Add wine; stir until absorbed, about 1 minute. Add 1 1/2 c warm broth; cook until absorbed, stirring often, about 5 minutes. Add more broth, 1/2 cupful at a time, allowing each addition to be absorbed before adding next and stirring often, until rice is just tender and mixture is creamy, about 20 minutes longer.
Remove from heat; stir in cheese and 1 butter. Season with salt and pepper. Transfer to bowl and serve.