Soak skewers in water for 30 minutes. Cut sausage links into 1-inch rounds. Core but don't peel apples. Cut each into 8 equal wedges. Cover wedges with water in a large bowl and stir in lemon juice. Set aside.
Peel onion and cut off root and stem ends. Cut onion into 8 equal wedges, stem to root.
Heat grill to medium-high (375 to 400 degrees). Thread ingredients on bamboo skewers: sausage, apple wedge, onion wedge. Repeat so each skewer has two pieces of each ingredient. Finish skewer with one more sausage round.
Brush skewers lightly with Apple Thyme Glaze. Grill 3 to 4 minutes. Turn skewers over and brush again with glaze. Grill 3 to 4 more minutes. Brush once more with glaze just before removing skewers from grill.
Apple Thyme Glaze
2 C apple juice
1 C apple brandy
4 T honey
2 T minced shallot
1 T fresh thyme leaves
Bring apple juice, brandy, honey and shallot to a boil in a small saucepan over medium-high heat. Vigorously simmer until liquid is reduced to 1 cup, about 20 to 25 minutes.
Stir in thyme leaves and remove from heat to cool.
May be made up to 3 days in advance. Store covered in the refrigerator. Bring to room temperature before using.