He was born in London England on 3 March 1852 to Edward Palmer and his wife Caroline He was educated at Lancing College Sussex before joining the financial department of the Indian government in 1871 He became assistant Comptroller-General before leaving India for Egypt in 1855 Here he succeeded Sir Gerald FitzGerald KCMG as director-general of accounts in Egypt He was made CMG in 1888 and a year later succeeded Sir Edgar Vincent 1st Viscount D'Abernon as financial advisor to the Khedive

Sir Elwin was appointed first governor to the newly created National Bank of Egypt in 1898. In 1902 he was appointed president of the Agricultural Bank of Egypt a subsidiary of the National Bank He was made KCMG in 1892 and KCB in 1897 whilst also being awarded the grand cordens of the Osminieh Order and the Order of Medjidie

He married Mary Augusta Lynch Clogstoun daughter of Major Herbert Mackworth Clogstoun VC and Mary Julia MacKenzie (a niece of photographer Julia Margaret Cameron), on 27 August 1881 in Madras India

He died in Cairo on 28 January 1906