In her book, Jane Austen and the Clergy, Irene Collins writes: Clergymen in Jane Austen’s day were not expected to write original sermons every Sunday. “Henry Crawford, assessing Edmund Bertram’s commitments at Thornton Lacey, judged that ‘a sermon at Christmas and Easter ‘would be’ the sum total of the sacrifice.” Mr. Collins produced only two sermons between his ordination at Easter and his visit to Longbourn in November of the same year.- p. 96.
Jane Austen herself mentions Easter, most notably in Pride and Prejudice:
In this quiet way, the first fortnight of her visit soon passed away. Easter was approaching, and the week preceding it was to bring an addition to the family at Rosings, which in so small a circle must be important. Elizabeth had heard, soon after her arrival, that Mr. Darcy was expected there in the course of a few weeks, and though there were not many of her acquaintance whom she did not prefer, his coming would furnish one comparatively new to look at in their Rosings parties, and she might be amused in seeing how hopeless Miss Bingley’s designs on him were, by his behaviour to his cousin, for whom he was evidently destined by Lady Catherine; who talked of his coming with the greatest satisfaction, spoke of him in terms of the highest admiration, and seemed almost angry to find that he had already been frequently seen by Miss Lucas and herself.
Colonel Fitzwilliam’s manners were very much admired at the parsonage, and the ladies all felt that he must add considerably to the pleasure of their engagements at Rosings. It was some days, however, before they received any invitation thither, for while there were visitors in the house they could not be necessary; and it was not till Easter-day, almost a week after the gentlemen’s arrival, that they were honoured by such an attention, and then they were merely asked on leaving church to come there in the evening. For the last week they had seen ver little of either Lady Catherine or her daughter. Colonel Fitzwilliam had called at the parsonage more than once during the time, but Mr. Darcy they had only seen at church.
The invitation was accepted of course, and at a proper hour they joined the party in Lady Catherine’s drawing room. Her ladyship received them civilly, but it was plain that their company was by no means so acceptable as when she could get nobody else; and she was, in fact, almost engrossed by her nephews, speaking to them, especially to Darcy, much more than to any other person in the room.
Ellen Moody noted that dating Sense and Sensibility presented a problem. It was revised several times and as a result the chronology remains inconsistent. Towards the book’s end, Easter is mentioned as occurring on March 31. This would have fallen in 1793, when the first draft of the novel was written. But, there is another reference to Easter in early April, which would have placed the novel in 1798 (the most likely), 1801, 1803, and 1809.
More on the topic:
Jane Austen’s Easter: Jane Austen Centre Online Magazine