There is much ambiguity concerning the responsibilities of the CIO and the CTO but that should not preclude one or the other from the planning and development of a technology that will radically change the way the company goes about doing its business. Both these positions are on the chief executive level and while the CTO will be more concerned about the technologies involved in the cloud, the CIO will be concerned about how the information will be handled, stored, and accessed. Leaving out either one will leave areas within the changeover that could cause some serious hold ups in the migration phase of the project. In my experience as a CTO, such major efforts need all the chief level executives involved in the changeover.
In your example, the CIO is responsible for ???defining policies regarding the management and governance of information assets.??? Without the input from the CIO, the company could commit itself to a contract that does not meet all the management and governance issues the policies and procedures are set up to handle so everything meets the criteria of federal, state, and corporate mandates. The CIO is the expert in this area and the expert in the technologies is the CTO. Working side by side they would be much more certain of creating a much more viable situation. With the input from the CFO, they would have a financial basis of what they could work with.