Born in 1856, Lorimar was a painter of portraits and contemporary genre, particularly featuring "the more refined and cultured side of modern society".
Born in Edinburgh to Professor James Lorimar, he studied at the Royal Scottish Academy under McTaskert and in Paris under Carole Duran. He toured extensively in Europe, including visits to Spain in 1877, Italy in 1882 and Algiers in 1891. He exhibited with the Royal Scottish Academy from 1873 and at the Royal Academy from 1878.
An Associate of the Royal Scottish Academy from 1882, he was made a full Member in 1900. He was also a Member of the Royal Society of Painters and Etchers and an Associate of the Royal Water-colour Society.
In his early years he concentrated on portraiture and flower painting, and made a great study of tone. Later he won distinction as a painter of contemporary genre, mainly scenes of Scottish middle-class home life, as typified by his 1890 painting, Grandmother's Birthday. He was always much concerned with the effects of light and his interiors especially, both in oils and water-colours, are luminous and transparent.
His work was very popular in France and, in partaking in exhibitions abroad, he came to be associated with the members of the Glasgow school including Sir James Guthrie, Sir John Lavery and Joseph Crawhall.