"Rousseau saw self-analysis and self-revelation essential,....and love [correctly seen] as a physical passion...[There is] within French romanticism and within Lamartine's writings. [in the words of another Lamartine biographer] an alienation from and disillusion with society, belief in God's presence in nature and striving for mystical union between man and God.'"
After 1831 Lamartine was writing on social causes, the problems of the urban poor, and in addition to his poetic career, participating as a member of the governmemt, particularly the Second Republic, serving as a diplomat as well as other roles. His later years though were spent in obscurity as political fashions shifted.
Here is an excerpt from Lamartine's memoirs, Twenty-five years of my life [English translation 1872]. This lengthy quote has a flimsy cat reference so if you are not interested in an evocation of a 19th century French chateau, you needn't read further. Lamartine is describing his childhood home.
From the window to the north of the drawing-room the view was wide and beautiful. It looked over the village to the slopes of the vineyards intermingled with crops of oats and beans; and then rested on the towers of an old Gothic chateau perched on a ledge of dark pointed rocks, called the Chateau de Berze\ which was looked upon as the great landmark of the country side. Its high-pitched roofs and pointed towers were grouped together like the folds of a great mushroom of wood and stone and rock; so that the eye rested upon it involuntarily and returned to it again and again. It was like a voice from the Middle Ages speaking of times long since past, and stretching on to the future, defying ruin or forgetfulness. The very sight of it had all the gravity of history. Against the dark pine forest it seemed like a group of Ossian's—as marvellous and as indestructible. This ruinous chateau was the property of the old Count of Pierreclos, one of the oldest and noblest families in the country. It added the solemnity of the past and a kind of austere sadness to the varied and radiant aspect of the rest of the country.