Allow me to back up a bit. A soliciting corporation is actually easier to define. A soliciting corporation is a corporation that receives money from the public, or from a government grant of any level of government, or from another corporation that receives money from the public or gets a government grant.
Non-soliciting corporations are everybody else. A curling club, for example, which is strictly funded by the donations or the dues of its members, would be non-soliciting. An airport or a port would, under this act, be non-soliciting, if it's self-financing. There are golf clubs; there are various service organizations.