For several years of his life we know little about Lovecraft. Yet between his writing of the Alchemist (1908) and The Tomb June 1917). Lovecraft was an avid (maybe even a rabid) reader of the news, yet few newsworthy episodes seemed to impact him and his writing. More likely, a small bit of flotsam would cross his path and it would set off a compulsive impulse to create a horror story.
All things British fascinated him, albeit in a philosophical view. The death of Victoria was a significant world event ... the ascent of Edward VII on 22 January 1901 (Lovecraft being 10) and then the ascent of George V (b 1865, d1936) on 6 May 1910. This may have intrigued the 19 year old Lovecraft as this marked the formation of the House of Windsor with deep Germanic roots. This shattered the Hanoverian era (1714 to 1901) containing two of the longest reigning monarchs - George III (b1738, k1760, d1820) and Victoria (b1819, q1837, d1901). Conversely, it might have swelled HPL's pride in Aryanism.
As late as January 1916, Lovecraft wrote the poem "An American to Mother England". From British bodies, minds, and souls I come, // And from them draw the vision of their home.
Lovecraft (at least) once remarked that he was loyal to George III, a reference as if he were a loyalist during the Revolutionary War.
On this date, 15 July 1910, the coronation of George V would be announced and would follow on the next year 22 June 1911. This postcard commemorated that date.