Elsie Marian Henderson [also known as Baroness de Coudenhove] was born in Eastbourne, East Sussex, England on 28 May 1880. By 1901 she had moved to Guernsey in the Channel Islands. Her address that year was given as "Rosenheim", St. Andrews, Guensey in the England and Wales census that year. By 1903 she had moved to London and from 1903 to 1905 studied at the Slade School of Fine Art, University College London. In 1908-09 she lived in Paris where she attended the Atelier Colarossi and Académie Moderne. She returned to Paris in 1912 and took lessons with the Fauvist painter Achille-Émile Othon Friesz (1879-1949). She then spent a period painting in Italy and Germany. In c.1914 she returned to Guernsey. By 1916 she was back in London and enrolled at Chelsea Polytechnic in London, where she trained in lithography under Francis Ernest Jackson (1872-1945). In 1920 she started her own press.
Henderson became known for her animal drawings and in 1917 she was commissioned by London Transport to design a poster showing the animals and birds of London.
She exhibited at the Goupil Gallery, Grosvenor Gallery, International Society of Sculptors, Painters and Gravers, Redfern Gallery, Royal Academy, London Salon, Leicester Galleries, New English Art Club, and Society of Women Artists in London; Royal Glasgow Institute for the Fine Arts; Walker Art Gallery in Liverpool; and at the Royal Scottish Academy in Edinburgh. A solo exhibition of her drawings, lithographs and sculptures of wild animals was held at the Leicester Galleries in London in 1924.
She was a member of the Women's Guild of Arts, Senefelder Club, Monarro Group, Women's International Art Club and the Society of Graver-Printmakers in Colour. She lived in London until 1928 when she married Henri, Baron de Coudenhove (1872-1946), the French Consul in Guernsey. Later that year she returned to Guernsey with him.
Following the death of her husband, in 1946, she moved back to East Sussex and settled in Hadlow Down. She died in Tunbridge Wells, Kent on 1 July 1967. Her address at the time of her death was Sunnyside Cottage, Hadlow Down, East Sussex.
