I was also at first a bit surprised at Elinor's readiness to forgive Edward. But I guess I tend to think (someone else mentioned this before I believe) that she thinks of Edward as innocent, and part of that may also be because Elinor, like Jane Bennet, does not show her feelings to their full extent. And while Jane B may blame herself, Elinor may be aware of that - she is a great observer of those she interacts with, so she could recognize that Edward loved her inspite of her cautious return of affection. Edward loves Elinor inspite of the reserve. Elinor loves Edward inspite of his. Marianne had a point about Elinor's concealment where Marianne told all. And Elinor is patient, with low or at least more realistic expectations.