Here is what I can say. By the time that chapter comes around, Almondine exists in a state where the literal and figurative, the subjective and objective, the past, present and future, all intersect. She lives balanced between sorrow and hope, waiting and acting, and she has to make a choice. In my experience, a brokenhearted dog will simply lie down and not move. A dog with some degree of hope about the world will be up and looking around. Almondine chooses the latter. She begins to search, not just for Edgar but for a solution to the whole quandary of being without Edgar, about being separated from one's purpose in life, which is something larger and more profound than physical separation—and a question that Edgar himself happens to be grappling with at that moment. So I can't agree that Almondine dies of a broken heart. She's acting too much on her own behalf for that to be true.
However, I'd also point out that Almondine has always had a singular ability to intuit where Edgar is going to be. At some level she knows "(bright flames)" where she will find him and has concluded that if he can't come to her, she can go to where he will eventually be. When she steps onto the road, asking her question and solving her problem become one and the same.