February 20, 1882
Richard Ellmann in his biography Oscar Wilde, which contains one of the four previously published chronologies of the lecture tour, says that Wilde lectured in Columbus, OH, on February 20, 1882 . This is incorrect—Wilde was in Cincinnati on that day, although not to lecture. It was only as a stopover on his way to Louisville, KY where he lectured on the following night. (Wilde did return to Cincinnati to lecture, as he had planned to do, on February 23.)
But Wilde was not idle on this stopover visit to Cincinnati.
Upon arrival he checked into the Burnet House, before driving out to the famous Rookwood Pottery, where he met a talented artists he was to befriend later in New York [blog article]. Wilde returned to his hotel in the late afternoon to give an interview to The Cincinnati Enquirer. In the evening he visited the Cincinnati Music Hall to attend the opera  as an honored guest in the director's box.
Singing that night was Adelina Patti (1843—1919) the highly acclaimed Italian opera singer (born in Spain) who was professionally known simply as Patti. She remains one of the most famous sopranos in history owing to the purity and beauty of her lyrical voice and the unmatched quality of her bel canto technique. The composer Giuseppe Verdi, writing in 1877, described her as being perhaps the finest singer who had ever lived and a "stupendous artist".
Like Wilde she was a client of the theatrical impresario Richard D'Oyly Carte, and also a guest at The Burnet House in Cincinnati where Wilde stayed for his first lecture there.
The concert that Wilde attended was a closing entertainment of selected arias by leading singers from the previous week's Cincinnati Opera Festival. Madame Patti chose "Bel Raggio" from Semiramide by Rossini.
Afterwards, Wilde was taken backstage to be introduced to her—the diva must have made an impression on Wilde as he mentioned her in glowing terms in his only novel The Picture of Dorian Gray:
The Cincinnati Enquirer, 21 February 1882, 4.
"Dorian, you mustn't let this thing get on your nerves. You must come and dine with me, and afterwards we will look in at the opera. It is a Patti night, and everybody will be there. You can come to my sister's box. She has got some smart women with her."
"My dear Basil, how do I know?" murmured Dorian Gray, sipping some pale-yellow wine from a delicate, gold-beaded bubble of Venetian glass and looking dreadfully bored. "I was at the opera. You should have come on there. I met Lady Gwendolen, Harry's sister, for the first time. We were in her box. She is perfectly charming; and Patti sang divinely".
As an indication of the publicity engendered by Oscar Wilde in 1882, here we see fashion designs named for Wilde's friends Adelina Patti and Lillie Langtry, plus at least four inspired by Wilde himself. Others include the Hazel Kirke, which is the name of a play written by Wilde's friend and associate Steel Mackaye. Gerster would be Madame Etelka Gerster-Cardini the Hungarian prima donna.
For more on Wilde and fashion see The Philosophy of Dress.
Advertisement from The Atlanta Constitution (Atlanta, GA) February 22, 1882 p 7
The Cincinnati Enquirer, 21 February 1882, 2.
 Wilde actually did lecture in Columbus, OH on May 3, 1882.
 At the Great Music Hall (extant) not the Opera House where Wilde lectured two days later.