We can go a long way in moving towards an elected Senate without having the formal consent of the provinces. We can go a fair distance, as Bill C-20 does. However, on the distribution of the Senate seats, we need the consent of the provinces. There are hard constitutional constraints on what can be done without the consent of the provinces.
This is the trump card the provinces play. To use a baseball analogy, you can get to first base by yourself, but you can't get to second without bringing the provinces in. So the question is, when do you bring the provinces in? I think you bring them in after you have the process going. People could well differ on that assessment.