Will this apple plant flower without vernalization?

When I posted about my apple plant some time back, an amateur radio friend from the United States of America told me that apple requires vernalization for flowering. Orange plants may flower even without vernalization. What is this vernalization? Prolonged exposure to cold temperature in winter induces flowering in some plants in spring. That has been called vernalization. This fact explains why apple grows in regions with cold climate as in hill stations in this region. Yet this plant has been growing well in my backyard. I had seen a bigger plant grown in a large garden pot bearing a fruit in a local nursery. Not sure whether it was vernalized earlier from a hill station and brought over to the plains.