Internal IT department should be the experts in cloud computing. If client finds a cloud provider that is cheaper and better then internal IT department is not doing the job that it is being paid to do. As an IT Architect, I always investigate cloud option to meet client requirements. In general, cloud option is superior for small number of users or fluctuating load or both. Once clients realize that internal IT department is more knowledgeable than they are and internal IT department will choose cloud when cost and functionality justify it, clients will stop trying to circumvent internal IT department.