[4] According to family legend, Ernest was able to trace his ancestry to the important Torah scholar of the Middle Ages, Moses Maimonides, through his father and to the writer Sarah Trimmer through his mother.
[8] In 1910, when he was living at Winton, Woodside Park, London, and The Grove, West Mersea, Lazarus added his mother's maiden name of Barlow to his own by deed poll, becoming Ernest Arthur Lazarus-Barlow.
In 1898, he was one of the promoters of a bill in the House of Commons for the incorporation of a company to acquire land at Sookholme, near Warsop, on which to construct electricity generating equipment.
[12] In 1905, Lazarus helped the Wilderness Golf Club acquire land to the west of Blackett's Brook, adjacent to Manor House Farm in Friern Barnet, which was subsequently combined with John Miles's Manor House Farm estate to become the North Middlesex Golf Club.
He was a keen yachtsman, sailing his own boat off West Mersea, and was a member of the Corinthian and Southampton Yacht Clubs.