Trim the stems & the spiny tips off the artichoke, slice in half lengthwise
& rinse well under running water. Scrape out the choke. Using half a lemon
for each artichoke, squeeze the lemon juice over all the cut sides.

Using thick, heavy duty aluminum foil, make baking cups large enough to
hold each artichoke half. Place an artichoke half in each cup, cut side
up, sprinkle with garlic & a drizzle of olive oil over each one. Sprinkle
with salt & pepper. Add 2 tb of water to each half & cover the artichoke
halves with foil.

On a closed grill over medium-hot coals, grill the artichoke halves for 1
hour or until tender when pierced.

Kelly McCune, "Vegetables on the Grill"