She joined the Life Guards in 2020, winning the Sword of Honour at the Royal Military Academy Sandhurst as the best of her intake.
She played polo and hockey for the Army and took part in ceremonial duties, including Queen Elizabeth II’s funeral and the King’s coronation.
Lt Col Armitage said: “History may record Lizzie as the first female officer in the Army’s most senior regiment, but I know she would want to be recalled simply as a tough and talented young officer doing her utmost to serve King and country and to lead and inspire soldiers.
“Her sudden and untimely death leaves a huge void for all of us in the Household Cavalry family, and she will be remembered by us all as a lively, fun and dynamic officer with a very bright future ahead of her.”