Opposite Side Arm Spinning
In this 3rd option off the Straight Arm Elbow Lock, you can switch sides and attack for the armbar submission off someone who grabs their belt (gi) or shorts (no-gi).
Tim goes for the Straight Arm Elbow Lock...
Keep your knee up , and pull his arm tight against your bodywith your right arm. Repost the left hand to help with your base, and movement.
Bring your left foot around his body to the opposite side. You can grab the leg here with your left hand to help with control and spinning as well, but it is not necessary. Remember to keep a tight hold on his arm.
Your right foot should be in place to hold the head down. Your left leg can go over the body or just against the body. Keep the knees together and bridge up with the hips. Your right arm holds tightly against his arm for the lock. You can also keep his leg to help control him (shown in pic).