...SIL was saying that the provincial system generally covers you in emergencies, but once you're out of hospital, you're on your own....
The suggestion that Ontario's health insurance program covers only "emergencies" is too narrow, but it's true that provincial coverage throughout Canada tends to be less comprehensive than a typical health insurance plan in the United States (but also dramatically less expensive).
As you correctly indicate, each province has the constitutional authority to create its own healthcare system and to determine what public coverage, if any, it wants to offer to its residents. Indeed, "[
i]t would be open to [a province] to adopt a U.S.-style health care system. No one suggests that there is anything in our Constitution to prevent it".
Chaoulli v. Quebec (Attorney General), [2005] 1 SCR 791, 2005 SCC 35 at ¶ 176 (LeBel and Fish, JJ, dissenting but not on this point). The Canada Health Act, RSC 1985, c C-6 ("CHA") specifies the conditions under which the federal government will subsidise the healthcare system of a province, but that statute does not create any rights enforceable by ordinary people, because the power to enforce the statute is vested solely in the federal Governor in Council. CHA §§ 15-17. Thus, to determine what a province offers by way of public health coverage, one has to turn to the laws of that province.
Ontario's system of public health insurance is authorised by the Health Insurance Act, RSO 1990, c H.6 ("OHIA"). Every resident of Ontario is entitled to enroll in this insurance plan, subject to certain conditions. OHIA § 11(1). The plan covers not only emergency and medically necessary services, but also all other "[p]rescribed health care services rendered by prescribed practitioners under such conditions and limitations as may be prescribed". OHIA § 11.2(1)(3). The Ontario Lieutenant Governor in Council is authorised to make regulations "governing insured services, including specifying those services that are not insured services". OHIA § 45(1)(e). The regulations provide that many elective services are covered. For example, elective laboratory tests are generally covered if authorised by an appropriate professional. General, RRO 1990, Reg 552 ("Reg"), § 22(1). The regulations also incorporate by reference the contents of the "document published by the Ministry of Health and Long-Term Care titled 'Schedule of Benefits — Physician Services under the Health Insurance Act (October 1, 2005)'", including listed amendments thereto. Reg § 37.1. That document is
available online and appears to be 747 pages long, specifying a broad variety of covered services.