Unable to contact ATC; an IFR BE36 pilot suffered a close encounter with a high wing Cessna while attempting to re-establish ATC contact.

Narrative

On vectors with Houston approach. Did not hear from them for several minutes. I called several times and did not receive a reply. I knew from previous trips on that route that I should have been switched to another frequency by that time. I figured that due to my lower altitude in that same area I had lost contact with approach. I looked down to dial up the nearest frequency function in my KLN90B GPS and as I began dialing in that frequency to reestablish communication; I saw a high wing Cessna single appear from beneath my left wing moving toward the nose of my aircraft. The aircraft appeared closer than 500 ft and I pulled up from my assigned altitude to increase separation. I was then able to contact Houston approach on another frequency and I advised him that I had a visual on the aircraft in my area. The controller advised he had called me numerous times to report that traffic. I advised him that I had not been switched from the previous controller and that I was just reestablishing communication. From the angle that the other aircraft approached I believe his view of us was blocked by his right wing (High wing Cessna) and he was blocked from my view by my left wing (low wing Bonanza). I was monitoring guard frequency and never received a call from Houston if they ever realized that I was out of their communications. I don't believe the other aircraft was in communication with ATC or they would have vectored him around me since I was IFR and NORDO.