I can not find anything about her other than this portrait.
From bbc.co.
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The distinct A-line skirt and wide belt date this into the middle 1820s. Her neckline and sleeves are adorned with a lace bertha-epaulettes that would become immense in the late 1820s and early 1830s. Her sleeves and skirt show she is wearing a sheer over-dress.
Keywords: Lonsdale, Louisa Wildman, off shoulder straight neckline, bertha, epaulettes, over-dress, quarter length dual puffed sleeves, waist band, natural high waistline, A-line skirt, bodice ornament, bracelets, wrap