One possibility is Lt. Wm. J. Cloud of Gonzales County TX. He was in the 18th TX Cavalry and was captured at Arkansas Post. He was exchanged on or about May 4th 1863. He is in the hospital in Macon GA as of May 23, 1863. From that time forward, he is absent with leave in the Trans-Mississippi Dept (while his regiment remains with the Army of Tennessee). In 1864, he is authorized by Col Ford in San Antonio to raise a company of cavalry for three months special service and is thereafter referred to as captain. What makes him seem less likely is that Whaley (on behalf of Bourland) refers to "Mr." Wm Cloud instead of a military rank (e.g., Lt or Capt).