Grilled artichokes with garlic mayonnaise

For the garlic mayonnaise:
1/2 cup mayonnaise
1 clove garlic, minced
2 to 3 tablespoons orange juice
1 pinch salt
For the marinade:
1/4 cup extra virgin olive oil
2 tablespoons chopped fresh tarragon
Juice of 2 lemons
1/4 teaspoon salt
5 medium artichokes

1. To make the garlic mayonnaise: In a small bowl, combine the mayonnaise, garlic, orange juice, and salt. Refrigerate until needed.
2. To make the marinade: In a large bowl, whisk together the olive oil, tarragon, lemon juice, and salt. Set aside.
3. Trim bottom outer leaves from artichokes and cut off any spiny leaf tips with kitchen sheers. Peel stems. Cut artichokes in half and with a small, sharp knife, scoop out and discard the hairy chokes. Add artichoke halves to the large bowl and toss with the olive oil mixture to prevent discoloration. Marinate in olive oil mixture at room temperature for 1 hour. Remove from bowl; reserve marinade.
4. Place artichoke halves in center of cooking grate. Grill until tender, about 20 to 25 minutes, basting frequently with reserved olive oil marinade.
5. Serve grilled artichokes with any remaining marinade and garlic mayonnaise.